Cartilage repair apparatus and method

ABSTRACT

An orthopaedic device for repairing and regenerating cartilage includes a plug configured to be positioned in a hole formed in the cartilage and an anchor configured to support the plug. One or both of the plug and the anchor may be formed from naturally occurring extracellular matrix such as small intestine submucosa. A method for repairing and regenerating cartilage is also disclosed.

This application is a continuation of U.S. patent application Ser. No.10/195,347, filed on Jul. 15, 2002, which claims priority under 35U.S.C. § 119(e) to U.S. Provisional Application No. 60/305,786, filedJul. 16, 2001, and to U.S. Provisional Application No. 60/389,027, filedJun. 14, 2002, the entirety of each of which is expressly incorporatedby reference herein.

CROSS REFERENCE

Cross reference is made to copending U.S. patent application Ser. No.10/195,795 entitled “Meniscus Regeneration Device and Method” (AttorneyDocket No. 265280-71141, DEP-745); Ser. No. 10/195,719 entitled “Devicesfrom Naturally Occurring Biologically Derived Materials” (AttorneyDocket No. 265280-71142, DEP-748); Ser. No. 10/195,344 entitled “UnitarySurgical Device and Method” (Attorney Docket No. DEP-750); Ser. No.10/195,341 entitled “Hybrid Biologic/Synthetic Porous ExtracellularMatrix Scaffolds” (Attorney Docket No. 265280-71144, DEP-751); Ser. No.10/195,606 entitled “Cartilage Repair and Regeneration Device andMethod” (Attorney Docket No. 265280-71145, DEP-752); Ser. No. 10/195,354entitled “Porous Extracellular Matrix Scaffold and Method” (AttorneyDocket No. 265280-71146, DEP-763); Ser. No. 10/195,334 entitled“Cartilage Repair and Regeneration Scaffolds and Method” (AttorneyDocket No. 265280-71180, DEP-763); and Ser. No. 10/195,633 entitled“Porous Delivery Scaffold and Method” (Attorney Docket No. 265280-71207,DEP-762), each of which is assigned to the same assignee as the presentapplication, each of which is filed concurrently herewith, and each ofwhich is hereby incorporated by reference. Cross reference is also madeto U.S. patent application Ser. No. 10/172,347 entitled “HybridBiologic-Synthetic Bioabsorbable Scaffolds” which was filed on Jun. 14,2002, which is assigned to the same assignee as the present application,and which is hereby incorporated by reference.

FIELD OF THE DISCLOSURE

The present disclosure relates generally to devices for attaching,repairing, or regenerating damaged or diseased cartilage.

BACKGROUND

Articular cartilage is a type of hyaline cartilage that lines thesurfaces of the opposing bones in a diarthrodial joint (e.g. knee, hip,shoulder, etc.). Articular cartilage provides a near-frictionlessarticulation between the bones, while also functioning to absorb andtransmit the compressive and shear forces encountered in the joint.Further, since the tissue associated with articular cartilage isaneural, these load absorbing and transmitting functions occur in apainless fashion in a healthy joint.

However, when articular cartilage tissue is no longer healthy it cancause debilitating pain in the joint. Cartilage health can be affectedby disease, aging, or trauma, all of which primarily involve a breakdownof the matrix consisting of a dense network of proteoglycan aggregates,collagen type II fibers, and other smaller matrix proteins. Cartilagecells, called chondrocytes, are unable to induce an adequate healingresponse because they are unable to migrate, being enclosed in lacunaesurrounded by a dense matrix. Further, since the tissue is avascular,initiation of healing by circulating cells is not possible.

Several cartilage repair strategies have been attempted in the past.These include surgical techniques such as microfracturing or performingan abrasion arthroplasty on the bone bed to gain vascular access, andhence, stimulate extrinsic repair in the defective region.

Another surgical technique is mosaicplasty or osteochondral autografttransfer system (OATS). In this case, cylindrical plugs of healthycartilage from a low-load bearing region of the knee are taken andtransplanted into the defective region.

The only FDA-approved cartilage treatment in the market involvesautologous chondrocyte implantation (CartiCel™). Autologous chondrocyteimplantation involves performing an initial biopsy of healthy cartilagefrom the patient, isolating the cells from the tissue, expanding thecells in vitro by passaging them in culture, and then reintroducing theminto the defective area. The cells are retained within the defect byapplying a periosteal tissue patch over the defect, suturing the edgesof the patch to the host tissue, and then sealing with fibrin glue. Thehealing observed is similar to that observed with microfracture orabrasion of the bone bed, indicating that it is the preparation of thebone bed and not the introduction of the cells that facilitates thehealing process.

Tissue engineering strategies for healing cartilage are beinginvestigated by several academic and commercial teams and show somepromise. The approach primarily involves using a carrier or a scaffoldto deliver cells or stimulants to the defect site. The scaffold materialcan be a purified biologic polymer in the form of a porous scaffold or agel (purified collagens, glycoproteins, proteoglycans, polysaccharides,or the like in various combinations) or porous scaffolds of syntheticbiodegradable polymers (PLA, PGA, PDS, PCL, or the like in variouscombinations). Several challenges remain with this approach, however.Some of these challenges include retention of the active stimulant atthe defect site, inability to control the rate of release of thestimulant (resulting in tissue necrosis due to overdose), cytotoxicityof the cells due to the degradation by-products of the syntheticpolymers.

As alluded to above, it is known to use various collagen scaffolds toprovide a scaffold for repair and regeneration of damaged tissue. U.S.Pat. No. 6,042,610 to ReGen Biologics, hereby incorporated by reference,discloses the use of a device comprising a bioabsorbable material madeat least in part from purified natural fibers. The purified naturalfibers are crosslinked to form the device. The device can be used toprovide augmentation for a damaged meniscus. Related U.S. Pat. Nos.5,735,903, 5,479,033, 5,306,311, 5,007,934, and 4,880,429 also disclosea meniscal augmentation device for establishing a scaffold adapted foringrowth of meniscal fibrochondrocyts.

It is also known to seed collagenous scaffolds with cells. See, e.g.,U.S. Pat. Nos. 6,379,367 and 6,283,980, the disclosure of each of whichis hereby incorporated by reference.

It is also known to use naturally occurring extracelluar matrices (ECMs)to provide a scaffold for tissue repair and regeneration. One such ECMis small intestine submucosa (SIS). SIS has been used to repair,support, and stabilize a wide variety of anatomical defects andtraumatic injuries. Commercially available SIS material is derived fromporcine small intestinal submucosa that remodels to the qualities of itshost when implanted in human soft tissues. Further, it is taught thatthe SIS material provides a natural scaffold-like matrix with athree-dimensional microstructure and biochemical composition thatfacilitates host cell proliferation and supports tissue remodeling.Indeed, SIS has been shown to contain biological molecules, such asgrowth factors and glycosaminoglycans, that aid in the repair of softtissue in the human body. SIS products, such as OASIS and SURGISIS, arecommercially available from Cook Biotech Inc., Bloomington, IN.

Another SIS product, RESTORE® Orthobiologic Implant, is available fromDePuy Orthopaedics, Inc. in Warsaw, Indiana. The DePuy product isdescribed for use during rotator cuff surgery, and is provided as aresorbable framework that allows the rotator cuff tendon to regenerate.The RESTORE Implant is derived from porcine small intestine submucosa, anaturally occurring ECM (composed of mostly collagen type I (about 90%of dry weight), glycosaminoglycans and other biological molecues) thathas been cleaned, disinfected, and sterilized. During seven years ofpreclinical testing in animals, there were no incidences of infectiontransmission from the implant to the host, and the SIS material has notadversely affected the systemic activity of the immune system.

While small intestine submucosa is available, other sources of ECM areknown to be effective for tissue remodeling. These sources include, butare not limited to, stomach, bladder, alimentary, respiratory, andgenital submucosa, and liver basement membrane. See, e.g., U.S. Pat.Nos. 6,379,710, 6,171,344, 6,099,567, and 5,554,389, hereby incorporatedby reference. Further, while SIS is most often porcine derived, it isknown that these various submucosa materials may be derived fromnon-porcine sources, including bovine and ovine sources. Additionally,the ECM material may also include partial layers of laminar muscularismucosa, muscularis mucosa, lamina propria, stratum compactum layerand/or other such tissue materials depending upon other factors such asthe source from which the ECM material was derived and the delaminationprocedure.

For the purposes of this disclosure, it is within the definition of anaturally occurring ECM to clean and/or comminute the ECM, or tocross-link the collagen within the ECM. However, it is not within thedefinition of a naturally occurring ECM to separate and purify thenatural fibers and reform a matrix material from purified naturalfibers. Also, while reference is made to SIS, it is understood thatother naturally occurring ECMs, such as stomach, bladder, alimentary,respiratory, or genital submucosa, or liver basement membrane, forexample, whatever the source (e.g. bovine, porcine, ovine, etc.) arewithin the scope of this disclosure. Thus, as used herein, the terms“naturally occurring extracellular matrix” or “naturally occurring ECM”are intended to refer to extracellular matrix material that has beencleaned, disinfected, sterilized, and optionally cross-linked. The terms“naturally occurring extracellular matrix” and “naturally occurring ECM”are also intended to include ECM foam material prepared as described incopending U.S. patent application Ser. No. 10/195,354 entitled “PorousExtracellular Matrix Scaffold and Method” (Attorney Docket No.265280-71146, DEP-747), filed concurrently herewith.

The following patents, hereby incorporated by reference, disclose theuse of ECMs for the regeneration and repair of various tissues:6,379,710; 6,187,039; 6,176,880; 6,126,686; 6,099,567; 6,096,347;5,997,575; 5,993,844; 5,968,096; 5,955,110; 5,922,028; 5,885,619;5,788,625; 5,733,337; 5,762,966; 5,755,791; 5,753,267; 5,711,969;5,645,860; 5,641,518; 5,554,389; 5,516,533; 5,460,962; 5,445,833;5,372,821; 5,352,463; 5,281,422; and 5,275,826.

It is known to use such materials as catgut and SIS to make appliances.See the Bolesky published application WO 95/06439. The Boleskyapplication discloses devices that are semi-rigid and are formed intodesired shapes, but Bolesky does not disclose a process for fabricatingnaturally occurring extracellular matrix parts so that they are rigidand hardened.

SUMMARY

The concepts of the present disclosure provide for an implantable,biodegradable cartilage repair device. In an illustrative embodiment,there is provided an implantable cartilage repair device which includesa plug formed of a naturally occurring extracellular matrix. The densityand porosity of the extracellular matrix material can be controlled withcompression drying, including air drying, air drying with heat, vacuumdrying, vacuum drying with heat, and freeze drying. Thus, the ECMmaterial can be dried to have a hardness sufficient to machine thedevice, without the need to form the device into the general shape bymolding. By managing density and porosity of the ECM various matricesand fixation devices may be fabricated having superior materialproperties which allow the device to promote healing while remainingbiodegradable.

In a more specific illustrative embodiment, there is provided anorthopaedic device for repairing and regenerating cartilage. The deviceincludes a plug configured to be positioned in a hole formed in thecartilage and an anchor configured to support the plug and engage thesubchondral bone. One or both of the plug and the anchor may be formedfrom naturally occurring extracellular matrix.

For example, a mass of naturally occurring ECM may be cured to be veryrigid and hardened so that it can be machined using conventional cuttingtools and/or laser machining. As such, the anchor and/or the plug may beformed by machining a mass of cured matrix to define the structuralfeatures thereof. The mass may be formed by compressing the ECM into asolid mass. For example, the ECM may be comminuted and formed into asolid mass with interlocking strands of ECM.

For example, a tightly balled up or compacted mass of pieces of SIS oreven comminuted SIS may be hardened by air drying or by hot air dryingto become extremely hard. Unexpectedly, this hardened SIS may bemachined or formed to have very sharp pointed ends, sharp barbs, etc.With this process, anchors, tacks, barbed tacks, and staples may bemachined from such cured mass of SIS.

In one embodiment, there is provided a device for repairing a diseasedor damaged portion of articular cartilage on a bone of a joint. Thecartilage is prepared by forming an opening therein to remove thediseased or damaged portion. The device includes a plug configured to bepositioned in the cartilage opening. The plug has generally the shape ofthe opening. The device also includes an anchor configured to positionand hold the plug in the opening. The plug is formed of naturallyoccurring extracellular matrix shaped and dried to have a structuralstrength sufficient to withstand the compression and shear stressesinvolved in the joint. The plug is secured to the anchor so as to be incontact with the bone.

In regard to another embodiment, there is provided a method forrepairing a diseased or damaged portion of articular cartilage on abone. The method includes the step of forming an opening in thearticular cartilage so as to remove the diseased or damaged portionthereof. The method also includes the step of positioning a plug in theopening so as to be adjacent healthy articular cartilage. The plug isformed of a naturally occurring extracellular matrix cured to have astructural rigidity to withstand the compression and shear stress placedon the articular cartilage.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross sectional view of a cartilage repair device implantedin subchondral bone, note that the anchor is shown in elevation ratherthan cross section for clarity of description;

FIGS. 2-4 are views similar to FIG. 1, but showing additionalembodiments of a cartilage repair device;

FIG. 5 is a cross sectional view of a cartilage repair device whichutilizes an alternative embodiment of an anchor;

FIG. 6 is a cross sectional view of a cartilage repair device whichutilizes an anchor in the form of a staple to secure the assembly to thesubchondral bone, note that FIG. 6 includes an encircled portion showinga perspective view of the staple and plug;

FIG. 7 is a cross sectional view of a cartilage repair device whichutilizes an anchor in the form of a ring to secure the assembly to thesubchondral bone;

FIGS. 8-10 are perspective views of a number of embodiments of the ringsof FIG. 7;

FIG. 11 is an enlarged perspective view of a cartilage repair devicewhich utilizes an alternative embodiment of an anchor, note that aportion of one of the tubes has been cut away for clarity of descriptionto expose the barb positioned therein;

FIG. 12 is a cross sectional view showing the cartilage repair device ofFIG. 11 secured to the native cartilage, note that the anchor is shownin elevation rather than cross section for clarity of description; and

FIG. 13 is a cross sectional view showing the cartilage repair device ofFIG. 11 secured to the subchondral bone, note that the anchor is shownin elevation rather than cross section for clarity of description.

DETAILED DESCRIPTION OF THE DRAWINGS

While the concepts of the present disclosure are susceptible to variousmodifications and alternative forms, specific embodiments thereof havebeen shown by way of example in the drawings and will herein bedescribed in detail. It should be understood, however, that there is nointent to limit the disclosure to the particular forms disclosed, but onthe contrary, the intention is to cover all modifications, equivalents,and alternatives falling within the spirit and scope of the disclosureas defined by the appended claims.

Referring now to FIG. 1, there is shown a cartilage repair device 10 forrepairing damaged or diseased cartilage. The device 10 includes ananchor 12 which is anchored or otherwise positioned in an opening formedin both a section of native cartilage 16 and the underlying subchondralbone 18. The anchor 12 is configured to be secured in an area from whichdamaged, diseased, or destroyed native cartilage and possibly bone havebeen removed. The anchor 12 includes an elongated central body portion20 and a head portion 22. The body portion 20 extends downwardly from alower surface of the head portion 22. As shown in FIG. 1, the bodyportion 20 may have a number of barbs 24 extending therefrom forengaging the sidewalls of the opening formed in the bone 18. In theillustrative embodiment described herein, the barbs 24 extend radiallyoutwardly and are inclined slightly toward the head portion 22 of theanchor 12.

The cartilage repair device 10 also includes a scaffold or plug 26. Theplug 26 is secured to the anchor 12. Specifically, the plug 26 issecured to the upper surface of the head portion 22 of the anchor 12.The plug 26 allows for communication across the removed portion (i.e.,the portion of the native cartilage 16 from which the damaged ordiseased cartilage has been removed) and the adjacent healthy cartilage.As such, the plug 26 functions as a chondrogenic growth-supportingmatrix for promoting a positive cellular response in an effort toachieve articular cartilage regeneration.

The anchor 12 of the cartilage repair device 10 may be constructed ofnumerous types of synthetic or naturally occurring materials. Forexample, the anchor 12 may be constructed with a bioabsorbable polymer.Examples of such polymers include: polyesters of[alpha]-hydroxycarboxylic acids, such as poly(L-lactide) (PLLA),polyglycolide (PGA); poly-p-dioxanone (PDO); polycaprolactone (PCL); andany other bioresorbable and biocompatible polymer, co-polymer or mixtureof polymers or co-polymers that are commonly utilized in theconstruction of prosthetic implants. Moreover, the anchor 12 may beconstructed with a naturally occurring material such as a naturallyoccurring ECM (e.g., SIS). In such a case, the head portion 22 and bodyportion 20 of the anchor 12 may be configured as monolithic structuresformed from naturally occurring ECM which is cured to be rigid andhardened to facilitate attachment to the bone 18. As such, it should beappreciated that the ECM material from which the anchor 12 is fabricatedis cured to produce a structure which possesses the necessary hardnessand toughness to allow the anchor 12 to be driven into bone tissue(i.e., the subchondral bone 18).

It should be understood that the material selected for the anchor 12 mayalso comprise mixtures or composites of materials. For example, theanchor 12 could comprise both a polymer and ECM material.

ECM material with the necessary hardness and toughness for use as theanchor 12, along with other devices constructed from ECM disclosedherein, may be fabricated by compacting comminuted or shredded naturallyoccurring ECM material into bar or rod stock by compressing the materialtogether and then curing the material such that it is very rigid andhardened. The curing may be accomplished by simple air drying or byheated air drying of the formed stock. Moreover, the entire structuremay be cross-linked.

In a specific exemplary embodiment, the anchor 12 may be constructedwith a cured and hardened SIS. In this case, comminuted SIS material isplaced in a container and allowed to air dry for a predetermined periodof time (e.g., as long as several days) at room temperature. Over such atime, water evaporates from the SIS material thereby shrinking thematerial. The shrunk material is very tough and hard and, as a result,may be machined as described herein.

It should be appreciated that other process parameters may beestablished to facilitate the curing process. For example, a curingprofile utilizing predetermined amounts of heat and/or pressure may bedesigned to facilitate the curing of the naturally occurring ECMmaterial (e.g., SIS).

Once the ECM material (e.g., SIS) is cured to a desired hardness andtoughness, it may be machined with conventional machining equipment todesired shapes. For example, the anchor 12 may be turned on a lathe orsimilar equipment to produce the desired configuration of the headportion 22 and the body portion 20 (including, for example, the barbs24). However, based on the specific design of the anchor 12, it shouldbe appreciated that certain features of the anchor 12 (e.g., the barbs24) may be separately or additionally machined to produce a desiredshape or geometry. For example, various barb configurations may beformed on the body portion 20 of the anchor 12 by, for example, use of acutting machine.

In addition to conventional machining techniques (e.g., lathing andcutting), contemporary techniques may also be utilized to form the curednaturally occurring ECM into the desired configuration of the anchor 12.For example, a programmable laser cutting machine may be utilized to cutthe raw stock of cured ECM. Specifically, the laser cutting machine maybe programmed to cut the raw stock in a pattern which produces a desiredconfiguration of the anchor 12. In addition to providing for cuttingwith precision tolerances, laser cutting also provides other benefits.For example, such laser cutting of the ECM products, for example, barbshaving cut edges which are sealed and fused together to enhance theattachment capability of the barbs. In addition, naturally occurring ECMcan be molded and cured into the desired shapes.

As alluded to above, the plug 26 functions as a chondrogenicgrowth-supporting matrix for promoting vascular invasion and cellularproliferation in an effort to achieve articular cartilage regeneration.A central body 30 of the plug 26 is configured as a porous structureconstructed from a naturally occurring ECM material such as SIS. Assuch, when anchored to a defective area of cartilage, cells can migrateinto and proliferate within the plug 26, biodegrade the plug 26 while,at the same time, synthesize new and healthy tissue to heal thedefective area. The plug 26 may be made out of comminuted and/orlyophilized naturally occurring ECM (e.g. SIS) with the desired porosityand material density. Specifically, the material density and/or porosityof the plug 26 may be varied to control cell migration andproliferation. The cells can migrate from adjacent tissue or fromsynovial fluid.

The plug 26 may additionally be chemically crosslinked with, forexample, aldehydes, carbodiimides, enzymes, or the like. The plug 26 mayalso be physically crosslinked. Physical crosslinking may beaccomplished by freeze-drying or fusing by physical means (e.g., thermalcrosslinking by the application of heat, radiation crosslinking by theapplication of ultraviolet or gamma irradiation, or dehydrothermalcrosslinking by the application of a combination of heat and drying).

The plug 26 may also include bioactive agents, biologically derivedsubstances (e.g. stimulants), cells, biologically compatible inorganicmaterials and/or biocompatible polymers.

“Bioactive agents” include one or more of the following: chemotacticagents; therapeutic agents (e.g. antibiotics, steroidal andnon-steroidal analgesics and anti-inflammatories, anti-rejection agentssuch as immunosuppressants and anti-cancer drugs); various proteins(e.g. short chain peptides, bone morphogenic proteins, glycoprotein andlipoprotein); cell attachment mediators; biologically active ligands;integrin binding sequence; ligands; various growth and/ordifferentiation agents (e.g. epidermal growth factor, IGF-I, IGF-II,TGF-β I-III, growth and differentiation factors, vascular endothelialgrowth factors, fibroblast growth factors, platelet derived growthfactors, insulin derived growth factor and transforming growth factors,parathyroid hormone, parathyroid hormone related peptide, bFGF;TGF_(β)superfamily factors; BMP-2; BMP-4; BMP-6; BMP-12; sonic hedgehog;GDF5; GDF6; GDF8; PDGF); small molecules that affect the upregulation ofspecific growth factors; tenascin-C; hyaluronic acid; chondroitinsulfate; fibronectin; decorin; thromboelastin; thrombin-derivedpeptides; heparin-binding domains; heparin; heparan sulfate; DNAfragments and DNA plasmids. If other such substances have therapeuticvalue in the orthopaedic field, it is anticipated that at least some ofthese substances will have use in concepts of the present disclosure,and such substances should be included in the meaning of “bioactiveagent” and “bioactive agents” unless expressly limited otherwise.

“Biologically derived agents” include one or more of the following: bone(autograft, allograft, and xenograft) and derivates of bone; cartilage(autograft, allograft and xenograft), including, for example, meniscaltissue, and derivatives; ligament (autograft, allograft and xenograft)and derivatives; derivatives of intestinal tissue (autograft, allograftand xenograft), including for example submucosa; derivatives of stomachtissue (autograft, allograft and xenograft), including for examplesubmucosa; derivatives of bladder tissue (autograft, allograft andxenograft), including for example submucosa; derivatives of alimentarytissue (autograft, allograft and xenograft), including for examplesubmucosa; derivatives of respiratory tissue (autograft, allograft andxenograft), including for example submucosa; derivatives of genitaltissue (autograft, allograft and xenograft), including for examplesubmucosa; derivatives of liver tissue (autograft, allograft andxenograft), including for example liver basement membrane; derivativesof skin tissue; platelet rich plasma (PRP), platelet poor plasma, bonemarrow aspirate, demineralized bone matrix, insulin derived growthfactor, whole blood, fibrin and blood clot. Purified ECM and othercollagen sources are also intended to be included within “biologicallyderived agents.” If other such substances have therapeutic value in theorthopaedic field, it is anticipated that at least some of thesesubstances will have use in the concepts of the present disclosure, andsuch substances should be included in the meaning of“biologically-derived agent” and “biologically-derived agents” unlessexpressly limited otherwise.

“Biologically derived agents” also include bioremodelable collageneoustissue matrices. The expressions “bioremodelable collagenous tissuematrix” and “naturally occurring bioremodelable collageneous tissuematrix” include matrices derived from native tissue selected from thegroup consisting of skin, artery, vein, pericardium, heart valve, duramater, ligament, bone, cartilage, bladder, liver, stomach, fascia andintestine, tendon, whatever the source. Although “naturally occurringbioremodelable collageneous tissue matrix” is intended to refer tomatrix material that has been cleaned, processed, sterilized, andoptionally crosslinked, it is not within the definition of a naturallyoccurring bioremodelable collageneous tissue matrix to purify thenatural fibers and reform a matrix material from purified naturalfibers. The term “bioremodelable collageneous tissue matrices” includes“extracellular matrices” within its definition.

“Cells” include one or more of the following: chondrocytes;fibrochondrocytes; osteocytes; osteoblasts; osteoclasts; synoviocytes;bone marrow cells; mesenchymal cells; stromal cells; stem cells;embryonic stem cells; precursor cells derived from adipose tissue;peripheral blood progenitor cells; stem cells isolated from adulttissue; genetically transformed cells; a combination of chondrocytes andother cells; a combination of osteocytes and other cells; a combinationof synoviocytes and other cells; a combination of bone marrow cells andother cells; a combination of mesenchymal cells and other cells; acombination of stromal cells and other cells; a combination of stemcells and other cells; a combination of embryonic stem cells and othercells; a combination of precursor cells isolated from adult tissue andother cells; a combination of peripheral blood progenitor cells andother cells; a combination of stem cells isolated from adult tissue andother cells; and a combination of genetically transformed cells andother cells. If other cells are found to have therapeutic value in theorthopaedic field, it is anticipated that at least some of these cellswill have use in the concepts of the present disclosure, and such cellsshould be included within the meaning of “cell” and “cells” unlessexpressly limited otherwise.

“Biological lubricants” include: hyaluronic acid and its salts, such assodium hyaluronate; glycosaminoglycans such as dermatan sulfate, heparansulfate, chondroiton sulfate and keratan sulfate; synovial fluid andcomponents of synovial fluid, including as mucinous glycoproteins (e.g.lubricin), vitronectin, tribonectins, articular cartilage superficialzone proteins, surface-active phospholipids, lubricating glycoproteinsI, II; and rooster comb hyaluronate. “Biological lubricant” is alsointended to include commercial products such as ARTHREASE ™ highmolecular weight sodium hyaluronate, available in Europe from DePuyInternational, Ltd. of Leeds, England, and manufactured byBio-Technology General (Israel) Ltd., of Rehovot, Israel; SYNVISC® HylanG-F 20, manufactured by Biomatrix, Inc., of Ridgefield, N. J. anddistributed by Wyeth-Ayerst Pharmaceuticals of Philadelphia, Pa.;HYLAGAN® sodium hyaluronate, available from Sanofi-Synthelabo, Inc., ofNew York, N.Y., manufactured by FIDIA S.p.A., of Padua, Italy; andHEALON® sodium hyaluronate, available from Pharmacia Corporation ofPeapack, New Jersey in concentrations of 1%, 1.4% and 2.3% (foropthalmologic uses). If other such substances have therapeutic value inthe orthopaedic field, it is anticipated that at least some of thesesubstances will have use in the concepts of the present disclosure, andsuch substances should be included in the meaning of “biologicallubricant” and “biological lubricants” unless expressly limitedotherwise.

“Biocompatible polymers” is intended to include both synthetic polymersand biopolymers (e.g. collagen). Examples of biocompatible polymersinclude: polyesters of [alpha]-hydroxycarboxylic acids, such aspoly(L-lactide) (PLLA) and polyglycolide (PGA); poly-p-dioxanone (PDO);polycaprolactone (PCL); polyvinyl alchohol (PVA); polyethylene oxide(PEO); polymers disclosed in U.S. Pat. Nos. 6,333,029 and 6,355,699; andany other bioresorbable and biocompatible polymer, co-polymer or mixtureof polymers or co-polymers that are utilized in the construction ofprosthetic implants. In addition, as new biocompatible, bioresorbablematerials are developed, it is expected that at least some of them willbe useful materials from which orthopaedic devices may be made. Itshould be understood that the above materials are identified by way ofexample only, and the present invention is not limited to any particularmaterial unless expressly called for in the claims.

“Biocompatible inorganic materials” include materials such ashydroxyapatite, all calcium phosphates, alpha-tricalcium phosphate,beta-tricalcium phosphate, calcium carbonate, barium carbonate, calciumsulfate, barium sulfate, polymorphs of calcium phosphate, ceramicparticles, and combinations of such materials. If other such substanceshave therapeutic value in the orthopaedic field, it is anticipated thatat least some of these substances will have use in the concepts of thepresent disclosure, and such substances should be included in themeaning of “biocompatible inorganic material” and “biocompatibleinorganic materials” unless expressly limited otherwise.

It is expected that various combinations of bioactive agents,biologically derived agents, cells, biological lubricants, biocompatibleinorganic materials, biocompatible polymers can be used with the devicesof the present disclosure.

Illustratively, in one example of embodiments that are to be seeded withliving cells such as chondrocytes, a sterilized implant may besubsequently seeded with living cells and packaged in an appropriatemedium for the cell type used. For example, a cell culture mediumcomprising Dulbecco's Modified Eagles Medium (DMEM) can be used withstandard additives such as non-essential aminoacids, glucose, ascorbicacid, sodium pyrovate, fungicides, antibiotics, etc., in concentrationsdeemed appropriate for cell type, shipping conditions, etc.

It should be understood that the material selected for the plug 26 mayalso comprise mixtures or composites of materials. For example, the plug26 could comprise both a polymer and ECM material.

The ECM from which the plug 26 is constructed may be confirmed to have astructural rigidity sufficient to withstand the compression and shearstress to which the cartilage 16 is subjected. Specifically, the plug 26in the illustrated embodiments has an outer surface which defines anarticular surface on which the cartilage from the other bone of thejoint bears. As such, the ECM from which the plug 26 is constructed tohave the structural rigidity necessary to bear the forces associatedwith the other bone.

One particularly useful material for fabricating the plug 26 is a porousscaffold or “foam” composed of naturally occurring ECM. For example, theplug 26 may be constructed from a porous SIS foam. In such a manner,both the material density and the pore size of the foam plug 26 may bevaried to fit the needs of a given plug design. Such foams may befabricated by lyophilizing (i.e., freeze-drying) comminuted ECM (i.e.,SIS) suspended in water. The material density and pore size of theresultant foam may be varied by controlling, amongst other things, therate of freezing of the comminuted SIS suspension and/or the amount ofwater or moisture content in the comminuted SIS at the on-set of thefreezing process.

The following is a specific example of a process for fabricating anexemplary SIS foam. The first step in developing a foam with a desiredpore size and density is the procurement of comminuted SIS. To do so,scissor-cut SIS runners (˜6″ long) are positioned in a 1700 seriesComitrol™ machine which is commercially available from UrschelLaboratories of Valpraiso, Indiana. The SIS material is processed andthereafter collected in a receptacle at the output of the machine. Thematerial is then processed through the machine a second time undersimilar conditions. The resultant material is a “slurry” of SIS material(thin, long SIS fibers ˜200 microns thick×1-5 mm long) suspendedsubstantially uniformly in water.

Thereafter, the comminuted SIS suspension is dried. To do so, alyophilization process (freeze drying) is used. In particular, the SISsuspension is frozen at a controlled temperature drop rate to controlthe size of the formed ice crystals. Without allowing the material tothaw, the process of lyopihlization sublimes ice crystals directly tovapor under vacuum and low temperatures. This leaves voids in the spacespreviously occupied by ice crystals. One exemplary machine forperforming such is a freeze drying process is a Virtis Genesis™ Serieslyophilizer which is commercially available from SP Industries, Inc. ofGardiner, N.Y.

The process parameters of the lyophilization process may be varied toproduce foams of varying pore sizes and material densities. For example,to produce foams having a relatively large pore size and a relativelylow material density, the comminuted SIS suspension may be frozen at aslow, controlled rate (e.g., −1° C./min or less) to a temperature ofabout −20° C. prior to lyophilization. To produce foams having arelatively small pore size and a relatively high material density, thecomminuted SIS may be tightly compacted by removing the water in asubstantially uniform manner so as to achieve a relatively high density.Thereafter, the comminuted SIS is flash-frozen using liquid nitrogenprior to lyophilization of the SIS. To produce foams having a moderatepore size and a moderate material density, the comminuted SIS is firsttightly compacted by removing the water in a substantially uniformmanner so as to achieve a relatively high density. Thereafter, the SISis frozen at a relatively fast rate (e.g., >−1° C./min) to a temperatureof about −80° C. prior to lyophilization of the SIS.

Additional techniques for forming such SIS foams in varying pore sizesand material densities are further described in copending U.S. patentapplication Ser. No. 10/195,354 entitled “Porous Extracellular MatrixScaffold and Method” (Attorney Docket No. 265280-71146, DEP-747), thedisclosure of which is hereby incorporated by reference.

In any case, once the plug 26 is fabricated, it is secured to the anchor12. To do so, the plug 26 may be secured to the anchor 12 in a number ofdifferent manners. For example, the plug 26 may be secured to the anchor12 by virtue of the lyophilization process. Alternatively, the plug 26may be mechanically secured to the anchor 12 such as by the use ofsutures or an adhesive. The plug 26 could also be captured between partsof the anchor 12. Crosslinking could also be used to secure the plug tothe anchor.

Referring now to FIG. 2, there is shown another embodiment of acartilage repair device (hereinafter referred to with reference numeral110). The cartilage repair device 110 is somewhat similar to thecartilage repair device 10. As such, the same reference numerals areutilized in FIG. 2 to identify components which have previously beendiscussed, with additional discussion thereof being unwarranted. Inaddition to the anchor 12 and the plug 26, the cartilage repair device110 includes a cover 34. The cover 34 may assume many differentconfigurations, one of which being a number of sheets 28. The cover 34is configured to have the structural integrity necessary to bear theforces associated with articulation with the other bone.

The cover 34 (e.g., the sheets 28) may also be utilized to secure theplug 26 to the anchor 12. In particular, as shown in FIG. 2, the sheets28 may be wrapped around the plug 26 and the head portion 22 of theanchor 12.

The cover 34 (e.g., the sheets 28) may be constructed of the same ordifferent ECM material as the plug 26 (e.g., SIS) and may be perforatedto allow easy chemical and cellular transfer. The cover 34 could also bemade of a synthetic biocompatible polymer. The cover 34 (e.g., thesheets 28) may be attached to the anchor 12 either by virtue of thelyophilization process or may be mechanically secured to the anchor 12such as by the use of sutures or an adhesive. The cover 34 may also bechemically or physically crosslinked in a similar manner to as describedabove in regard to the plug 26. Moreover, bioactive agents, biologicallyderived substances (e.g. stimulants), cells, biological lubricants,and/or biocompatible inorganic materials as defined above, may be addedto the sheets 28.

To produce the desired structural rigidity, the naturally occurring ECMmaterial from which the cover 34 (e.g., the sheets 28) is constructedmay be fabricated in a manner similar to as described above in regard tothe anchor 12 or the plug 26. Alternatively, the cover 34 may compriselayers 28 of material like the commercially available RESTORE productavailable from DePuy Orthopaedics of Warsaw, Ind. that have beenhardened. The cover 34 may also comprise a mixture or composite ofmaterials. For example, the cover 34 could comprise layers of bothpolymer and ECM material.

In an exemplary example of the embodiment of FIG. 2, the anchor 12 maybe constructed of PLLA, the plug 26 made of a cross-linked SIS foammaterial, and the cover 34 made of layers of SIS material like thecommercially available RESTORE product that has been hardened. The cover34 can also comprise an element shaped like the upper component 82 ofthe scaffold fixation device illustrated in FIGS. 7-9 and 11-13 of U.S.Pat. No. 6,371,958 B1, the complete disclosure of which is incorporatedby reference herein.

Referring now to FIG. 3, there is shown another embodiment of acartilage repair device (hereinafter referred to with reference numeral210). The cartilage repair device 210 is somewhat similar to thecartilage repair devices 10 and 110. As such, the same referencenumerals are utilized in FIG. 3 to identify components which havepreviously been discussed, with additional discussion thereof beingunwarranted. The cartilage repair device 210 utilizes a number of theECM sheets 28 as a chondrogenic growth supporting matrix. As such, thesheets 28 of ECM material function as a “plug” in a similar manner asthe plug 26. As shown in FIG. 3, the sheets 28 are secured to the anchor12 by wrapping the sheets 28 around the head portion 22 of the anchor12.

Similarly to as described above, the sheets 28 of ECM material of thecartilage repair device 210 may be perforated to allow easy chemical andcellular transfer. In addition to wrapping, the sheets 28 may be furthersecured to the anchor 12 either by virtue of the lyophilization processor may be mechanically secured to the anchor 12 such as by the use ofsutures or an adhesive. The sheets 28 may also be chemicallycrosslinked. Moreover, bioactive agents, biologically derived substances(e.g. stimulants), biological lubricants, cells, and/or biocompatibleinorganic materials as defined above may be added to the sheets 28.

Referring now to FIG. 4, there is shown another embodiment of acartilage repair device (hereinafter referred to with reference numeral310). The cartilage repair device 310 is somewhat similar to thecartilage repair devices 10, 110, and 210. As such, the same referencenumerals are utilized in FIG. 4 to identify components which havepreviously been discussed, with additional discussion thereof beingunwarranted. The cartilage repair device 310 is essentially the same asthe cartilage repair device 110 of FIG. 2, except for the configurationof the cover 34. In particular, the cover 34 (in this case, the sheets28 of naturally occurring ECM material) does not wrap around the edgesof the plug 26 (as does the cover 34 of FIG. 2). In such aconfiguration, the porous plug 26 is, in effect, sandwiched between atop cover and a bottom cover. The sheets 28 of the cartilage repairdevice 310, which in this exemplary embodiment function as the cover 34,may be constructed of the same or different ECM material as the plug 26(e.g., SIS) and may be perforated to allow easy chemical and cellulartransfer. The sheets 28 may be attached to the anchor 12 and/or the plug26 either by virtue of the lyophilization process or may be mechanicallysecured to the anchor 12 and/or the plug 26 such as by the use ofsutures or an adhesive. As described above, the cover 34 (e.g., thesheets 28) of the cartilage repair device 310 may also be chemicallycrosslinked. Moreover, bioactive agents, biologically derived substances(e.g. stimulants), cells, biological lubricants, biocompatible polymersand/or biocompatible inorganic materials as defined above may be addedto the cover 34. Yet further, the cover 34 of the cartilage repairdevice 310 may also be cured or otherwise fabricated to produce astructure with a desired structural rigidity.

Referring now to FIG. 5, there is shown another embodiment of acartilage repair device (hereinafter referred to with reference numeral410). The cartilage repair device 410 is somewhat similar to thecartilage repair devices 10, 110, 210, and 310. As such, the samereference numerals are utilized in FIG. 5 to identify components whichhave previously been discussed, with additional discussion thereof beingunwarranted. The cartilage repair device 410 includes an anchor 412which is utilized in lieu of the anchor 12 described in regard to FIGS.1-4. In particular, in the embodiment shown in FIG. 5, the plug 26 ispositioned in an osteochondral defect 414 without the use abottom-mounted anchor (i.e., the anchor 12 of FIGS. 1-4). Similarly toas described above, the plug 26 is constructed out of comminuted andlyophilized naturally occurring ECM (e.g., SIS) having a desiredporosity and material density.

The plug 26 is retained in the hole formed in the cartilage 16 andprotected from in vivo forces by an annular shaped anchor 412. Theanchor 412 may be provided in many different configurations which allowit to be press fit or otherwise anchored into the subchondral bone 18.For example, as shown in FIG. 5, the anchor 412 may be “bottlecap”-shaped so as to allow the anchor 412 to be press fit or otherwisesecured into an annular groove 416 formed in the subchondral bone 18.The groove may be formed and the anchor may be shaped as described andshown in Patent Cooperation Treaty publication WO 01/39694 A2, published7 Jun. 2001 entitled “Fixation Technology”, the complete disclosure ofwhich is incorporated by reference herein. Alternatively, the anchor 412may be mechanically secured to the subchondral bone 18 by use ofadhesive or other types of anchoring structures (e.g., barbs).

The anchor 412 of the cartilage repair device 410 may be constructedfrom numerous types of synthetic or naturally occurring materials. Forexample, the anchor 12 may be constructed with a bioabsorbable polymersuch as PLLA, PGA, PDO, PCL, or any other such bioabsorbable polymerwhich is commonly utilized in the construction of prosthetic implants.Moreover, the anchor 412 may be constructed from a naturally occurringmaterial such as a naturally occurring ECM (e.g., SIS) which is cured orotherwise fabricated to be rigid and hardened to facilitate attachmentto the bone in the same manner as described above in regard to theanchor 12 and/or the plug 26 of FIGS. 1-4.

In the case of when the anchor 412 is constructed from ECM, one or morelaminated or non-laminated sheets 28 of the same or different ECM may beutilized. The sheets 28 may surround the plug 26 on three sides, orperhaps all four sides. Alternatively, the anchor may be constructedfrom formed (e.g., dried and machined) comminuted ECM material. Ineither configuration, the ECM material may be perforated and may becured in a similar manner to as described above in regard to the anchor12 or the plug 26. As with the ECM material previously described above,the ECM material from which the anchor 412 is constructed may also bechemically crosslinked. Moreover, bioactive agents, biologically derivedsubstances (e.g. stimulants), cells, biocompatible polymers,biocompatible inorganic materials, and/or biological lubricants asdefined above may be added to the ECM material utilized to construct theanchor 412.

Referring now to FIG. 6, there is shown another embodiment of acartilage repair device (hereinafter referred to with reference numeral510). The cartilage repair device 510 is somewhat similar to thecartilage repair devices 10, 110, 210, 310, and 410. As such, the samereference numerals are utilized in FIG. 6 to identify components whichhave previously been discussed, with additional discussion thereof beingunwarranted.

The cartilage repair device 510 includes an anchor 512 which is somewhatsimilar to the anchor 412 described in regard to FIG. 5. In particular,in the embodiment shown in FIG. 6, the plug 26 is positioned in the holeformed in the cartilage 16 without the use a bottom-mounted anchor(i.e., the anchor 12 of FIGS. 1-4). However, in the case of thecartilage repair device 510 of FIG. 6, the anchor 512 is configured as astaple 520 which secures the plug within the defect 514.

Similarly to as described above, in this embodiment, the plug 26 may beconstructed from comminuted and lyophilized naturally occurring ECM(e.g., SIS) having a desired porosity and material density. As shown inFIG. 6, the plug 26 may be wrapped in a cover 34 such as a number ofsheets 28 of the same or different ECM which surround the plug 26. Itshould be appreciated that in a similar manner to the cartilage repairdevice 210 of FIG. 3, in lieu of a separate plug 26, the sheets 28 ofECM material themselves may function as a chondrogenic growth supportingmatrix.

The wrapped plug 26 (or similar matrix formed from the sheets 28) isretained in the defect 514 by inserting the staple 520 into thesubchondral bone 18. Alternatively, the wrapped plug 26 (or similarmatrix formed from the sheets 28) may be press fit or adhesively securedin the defect 514. In the case of a press fit plug, one or more groovesmay be formed in the sheets 28 to facilitate the press fit process.

The staple 520 of the cartilage repair device 510 may be constructed ofnumerous types of synthetic or naturally occurring materials. Forexample, the staple 520 may be constructed from a bioabsorbable polymersuch as PLLA, PGA, PDO, PCL, or any other such bioabsorbable polymerwhich is commonly utilized in the construction of prosthetic implants.Moreover, the staple 520 may be constructed from a naturally occurringmaterial such as a naturally occurring ECM (e.g., SIS) which is cured tobe rigid and hardened to facilitate attachment to the bone in the samemanner as described above in regard to the anchor 12 of FIGS. 1-4 andthe anchor 412 of FIG. 5.

The staple 520 can comprise a commercially available product, such as astaple available from the MITEK® Products division of ETHICON, INC. ofWestwood, Mass. Moreover, the staple 520 may be embodied as any of thestaples or other devices and methods disclosed in U.S. Pat. No.6,179,840 issued Jan. 30, 2001; U.S. Pat. No. 6,364,884 issued Apr. 2,2002; U.S. patent application Ser. No. 09/535,183 entitled “GraftFixation Device Combination” which was filed on Mar. 27, 2000; U.S.patent application Ser. No. 09/535,189 entitled “Instrument forInserting Graft Fixation Device” which was filed on Mar. 27, 2000; U.S.patent application Ser. No. 09/793,036 entitled “Graft Fixation DeviceCombination” which was filed Feb. 26, 2001; U.S. patent application Ser.No. 09/793,043 entitled “Methods of Securing a Graft Using a GraftFixation Device” which was filed on Feb. 26, 2001; U.S. patentapplication Ser. No. 09/793,216 entitled “Instrument for Inserting GraftFixation Device” which was filed on Feb. 26, 2001; U.S. patentapplication Ser. No. 09/864,619 entitled “Graft Fixation Device andMethod” which was filed on May 24, 2001; U.S. patent application Ser.No. 10/056,534 entitled “Graft Fixation Device Combination” which wasfiled on Jan. 24, 2002; and U.S. patent application Ser. No. 10/142,399entitled “Graft Fixation Device Combination” which was filed on May 9,2002, the disclosures of each of these patents and patent applicationsbeing hereby incorporated by reference.

Referring now to FIG. 7, there is shown another embodiment of acartilage repair device (hereinafter referred to with reference numeral610). The cartilage repair device 610 is somewhat similar to thecartilage repair devices 10, 110, 210, 310, 410, and 510. As such, thesame reference numerals are utilized in FIG. 7 to identify componentswhich have previously been discussed, with additional discussion thereofbeing unwarranted.

The cartilage repair device 610 includes an anchor 612 which, similarlyto the other anchors described herein, is utilized to retain the plug 26in an osteochondral defect 614. In the embodiment shown in FIG. 7, theanchor 612 is configured as a ring 620 which supports and secures theplug 26 within the defect 614.

Similarly to as described above, the plug 26 utilized in this, or anyother embodiment described herein, may be constructed out of comminutedand lyophilized naturally occurring ECM (e.g., SIS) having a desiredporosity and material density. As shown in FIG. 7, the plug 26 may bewrapped in a cover 34 such as a number of sheets 28 of the same ordifferent ECM material. It should be appreciated that in a similarmanner to the cartilage repair device 210 of FIG. 3, in lieu of aseparate plug 26, the sheets 28 of ECM material may themselves functionas a chondrogenic growth supporting matrix.

The wrapped plug 26 (or the matrix formed from the sheets 28) issupported and retained in the hole formed in the cartilage 16 byinserting the ring 620 into the hole. As shown in FIGS. 8-10, the ring620 may be embodied as a closed ring (see FIG. 8), a ring formed with aslot (see FIG. 9), or a ring formed with a taper (see FIG. 10). Suchmodifications may be utilized to enhance the retention characteristicsof the ring 620 in a given application.

The ring 620 of the cartilage repair device 610 may be constructed ofnumerous types of synthetic or naturally occurring materials. Forexample, the ring 620 may be constructed with a bioabsorbable polymersuch as PLLA, PGA, PDO, PCL, or any other such bioabsorbable polymerwhich is commonly utilized in the construction of prosthetic implants.Moreover, the ring 620 may be constructed with a naturally occurringmaterial such as a naturally occurring ECM (e.g., SIS) which is cured tobe rigid and hardened in the same manner as described above in regard tothe anchor 12 of FIGS. 1-4 and the anchors 412 and 512 of FIGS. 5 and 6,respectively. The inner space defined by the ring 620 may be filled withmaterial, such as ECM material (e.g., SIS), subsequent to implantationof the ring 620.

Referring now to FIGS. 11-13, there is shown another embodiment of acartilage repair device (hereinafter referred to with reference numeral710). The cartilage repair device 710 is somewhat similar to thecartilage repair devices 10, 110, 210, 310, 410, 510, and 610. As such,the same reference numerals are utilized in FIGS. 11-13 to identifycomponents which have previously been discussed, with additionaldiscussion thereof being unwarranted.

The cartilage repair device 710 includes an anchor 712 which, similarlyto the other anchors described herein, is utilized to retain the plug 26in an osteochondral defect 714. In the embodiment shown in FIGS. 11-13,the anchor 712 is configured as a ring 720 which has a number of barbs722 extending radially outwardly from a center of the ring 720. Inparticular, the ring 720 includes a ring body 724 and a number of tubes726. A first end portion 728 of each of the tubes 726 is positioned nearthe center point of the ring body 724, whereas a second end portion 730of each of the tubes 726 extends through the ring body 724.

One of the barbs 722 (or other type of engagement member) is positionedin each of the tubes 726. Each of the barbs 722 has a first end 734which is extendable out of the first end portion 728 of the tube 726,and a second end 736 which is extendable out of the second end portion730 of the tube 726. The second end 736 of the barbs 722 has a tip,point, or other type of engagement feature defined therein.

Each of the barbs 722 is positionable in either an extended position (asshown in FIGS. 12 and 13) or a retracted position (as shown in FIG. 11).When positioned in its extended position, the pointed end 736 of thebarb 722 extends out of the outer end of the tube 726 in which it ispositioned (see FIGS. 12 and 13). Conversely, when positioned in itsretracted position, the pointed end 736 of the barb 722 is retracted orotherwise received into the outer end of the tube 726 in which it ispositioned (see FIG. 11).

The barbs 722 may be selectively moved from their retracted positions totheir extended positions subsequent to positioning the ring 720 in thedefect. In particular, as shown in FIG. 11, the inner end 734 of thebarbs 722 has a cam surface 738 defined therein. In such a way,engagement of the cam surfaces 738 by a complimentary cam surface of anengagement tool (not shown) urges the barbs 722 radially outwardlythereby moving the barbs 722 from their respective retracted positionsto their respective extended positions. In an exemplary embodiment, theengagement tool has a spheroid-shaped engagement surface which, uponcontact with the cam surfaces 738 of the barbs 722, urges the barbs 722radially outwardly.

Similarly to as described above, the plug 26 utilized in this, or anyother embodiment described herein, may be constructed out of comminutedand lyophilized naturally occurring ECM (e.g., SIS) having a desiredporosity and material density. As shown in FIGS. 12 and 13, the plug 26may be wrapped in a cover 34 such as a number of sheets 28 of the sameor different ECM material. It should be appreciated that in a similarmanner to the cartilage repair device 210 of FIG. 3, in lieu of aseparate plug 26, the sheets 28 of ECM material may themselves functionas a chondrogenic growth supporting matrix.

The wrapped plug 26 (or the matrix formed from the sheets 28) issupported and retained in the hole formed in the cartilage 16 byinserting the ring 720 into the hole, and thereafter engaging thesidewall 740 in which the hole is formed with the barbs 722. Inparticular, once positioned in the hole, the barbs 722 may be urged fromtheir retracted positions to their extended positions thereby causingthe pointed ends 736 of the barbs 722 to engage the sidewall 740.

As shown in FIG. 12, the surgical site may be prepared such that thering 720, when implanted, engages the native cartilage 16.Alternatively, as shown in FIG. 13, the surgical site may be preparedsuch that the ring 720, when implanted, engages the subchondral bone 18.

The ring 720 of the cartilage repair device 710 may be constructed ofnumerous types of synthetic or naturally occurring materials. Forexample, the ring 720 may be constructed with a bioabsorbable polymersuch as PLLA, PGA, PDO, PCL, or any other such bioabsorbable polymerwhich is commonly utilized in the construction of prosthetic implants.

Moreover, the ring 720 may be constructed with a naturally occurringmaterial such as a naturally occurring ECM (e.g., SIS) which is cured tobe rigid and hardened in the same manner as described above in regard tothe anchor 12 of FIGS. 1-4 and the anchors 412 and 512 of FIGS. 5 and 6,respectively. The ECM material may be perforated and may be cured in asimilar manner to as described above in regard to the anchor 12 or theplug 26. As with the ECM material previously described above, the ECMmaterial from which the ring 720 is constructed may also be chemicallycrosslinked. Moreover, bioactive agents, biologically derived substances(e.g. stimulants), cells, biocompatible polymers, biocompatibleinorganic materials, and/or biological lubricants as defined above maybe added to the ECM material utilized to construct the ring 720.

The principles of the present disclosure may also be applied to othertypes of anchors. For example, cartilage repair units like thosedisclosed in U.S. Pat. No. 5,769,899 to Schwartz et al., the disclosureof which is incorporated by reference herein, can be made with a plug ofnaturally occurring extracellular matrix, with or without a cover. Inaddition, cartilage repair units like those disclosed in U.S. Pat. No.6,251,143 B1 to Schwartz et al., the disclosure of which is incorporatedby reference herein, can be made with an insert of naturally occurringextracellular matrix, with or without a cover. Reference is also made toU.S. Pat. No. 6,371,958 B1, discussed above; the entire scaffoldfixation device could be made of naturally occurring extracellularmatrix.

Hence, the cartilage repair devices described herein have numerousadvantages over heretofore designed devices. In particular, heretoforedesigned devices use, primarily, synthetic polymeric materials. However,synthetic polymers do not possess the advantages naturally occurringextracellular matrices (ECMs), like SIS, which can inherently stimulatecells to proliferate and to synthesize new tissue. However, one or bothof the plug and the anchor of the cartilage repair devices describedherein may be constructed out of a naturally occurring ECM material suchas SIS. Such a device provides an enhanced structure into which cellsmigrate, proliferate, and synthesize new tissue. Moreover, such a devicealso possess sufficient mechanical strength and degradation kinetics tosuccessfully withstand in vivo joint forces at least initially followingimplantation. In addition, for use in combination with devices such asthe scaffold fixation device disclosed in U.S. Pat. No. 6,371,958 B1,the plug should possess sufficient mechanical strength and degradationkinetics to successfully withstand the load provided by the anchoringdevice.

The concepts disclosed in the following copending U.S. patentapplications, which are incorporated by reference herein, may becombined with the teachings of the present disclosure: Ser. No.10/195,795 entitled “Meniscus Regeneration Device and Method” (AttorneyDocket No. 265280-71141, DEP-745); Ser. No. 10/195,719 entitled “Devicesfrom Naturally Occurring Biologically Derived Materials” (AttorneyDocket No. 265280-71142, DEP-748); Ser. No. 10/195,344 entitled “UnitarySurgical Device and Method” (Attorney Docket No. DEP-750); Ser. No.10/195,341 entitled “Hybrid Biologic/Synthetic Porous ExtracellularMatrix Scaffolds” (Attorney Docket No. 265280-71144, DEP-751); Ser. No.10/195,606 entitled “Cartilage Repair and Regeneration Device andMethod” (Attorney Docket No. 265280-71145, DEP-752); Ser. No. 10/195,354entitled “Porous Extracellular Matrix Scaffold and Method” (AttorneyDocket No. 265280-71146, DEP-747); Ser. No. 10/195,334 entitled“Cartilage Repair and Regeneration Scaffolds and Method” (AttorneyDocket No. 265280-71180, DEP-763); and Ser. No. 10/195,633 entitled“Porous Delivery Scaffold and Method” (Attorney Docket No. 265280-71207,DEP-762), along with U.S. patent application Ser. No. 10/172,347entitled “Hybrid Biologic-Synthetic Bioabsorbable Scaffolds” which wasfiled on Jun. 14, 2002. For example, it may be desirable to usebiological lubricants in combination with the concepts of the presentdisclosure.

For some cartilage repair applications, a repair may be made with aRESTORE™ wafer from DePuy Orthopaedics, Inc. which is seeded with cellsto encourage the healing process. For example, RESTORE™ wafers may beseeded with cells supplied by Verigen Transplantation ServiceInternational AG (VTSI) in Germany in accordance with processes offeredby VTSI. See U.S. Pat. Nos. 6,379,367 and 6,283,980, incorporated byreference herein. Illustratively, a 1.5 cm RESTORE™ wafer, which istypically made by laminating ten layers of SIS together, is supplied toVTSI to be seeded with cells.

Illustratively, therefore, a cartilage implant may comprise a laminateof a plurality of layers of ECM such as SIS, which laminate is seededwith cells such as chondrocyte cells.

While the concepts of the present disclosure have been illustrated anddescribed in detail in the drawings and foregoing description, such anillustration and description is to be considered as exemplary and notrestrictive in character, it being understood that only the illustrativeembodiments have been shown and described and that all changes andmodifications that come within the spirit of the disclosure are desiredto be protected.

There are a plurality of advantages of the present disclosure arisingfrom the various features of the cartilage repair devices describedherein. It will be noted that alternative embodiments of each of thecartilage repair devices of the present disclosure may not include allof the features described yet benefit from at least some of theadvantages of such features. Those of ordinary skill in the art mayreadily devise their own implementations of cartilage repair devicesthat incorporate one or more of the features of the present disclosureand fall within the spirit and scope of the appended claims.

1. A device for repairing a diseased or damaged portion of articularcartilage on a bone of a joint, the cartilage having been prepared byforming an opening therein to remove the diseased or damaged portion,the device comprising: a plug configured to be positioned in the openingformed in the cartilage, the plug defining a body of unseeded naturallyoccurring extracellular matrix, and an anchor configured to position andhold the plug in the opening.
 2. The device of claim 1, wherein thenaturally occurring extracellular matrix comprises comminuted naturallyoccurring extracellular matrix.
 3. The device of claim 2, wherein thecomminuted naturally occurring extracellular matrix is lyophilized. 4.The device of claim 1, wherein the naturally occurring extracellularmatrix comprises tissue selected from the group consisting of:vertebrate small intestine submucosa; vertebrate liver basementmembrane; vertebrate bladder submucosa; vertebrate stomach submucosa;vertebrate alimentary tissue; vertebrate respiratory tissue; andvertebrate genital tissue.
 5. The device of claim 4, wherein thenaturally occurring extracellular matrix comprises tissue selected fromthe group consisting of: bovine tissue; ovine tissue; and porcinetissue.
 6. The device of claim 1, wherein the anchor is formed ofnaturally occurring extracellular matrix cured and shaped to fasten intoa subchondral portion of the bone.
 7. The device of claim 6, wherein theanchor comprises (i) a head portion configured to support the plug, and(ii) a body portion extending from the head portion to fasten into thesubchondral portion of the bone.
 8. The device of claim 1, furthercomprising a cover disposed over at least part of an articular surfaceof the plug, wherein the cover comprises one or more sheets of naturallyoccurring extracellular matrix.
 9. A device for repairing a diseased ordamaged portion of articular cartilage on a bone of a joint, thecartilage having been prepared by forming an opening therein to removethe diseased or damaged portion, the device comprising: a plugconfigured to be positioned in the opening formed in the cartilage, theplug defining a body of naturally occurring extracellular matrix seededwith at least one of the following: a bioactive agent, a biologicallyderived substance, cells, a biological lubricant, a biocompatiblepolymer and a biocompatible inorganic material, and an anchor configuredto position and hold the plug in the opening.
 10. The device of claim 9,wherein the naturally occurring extracellular matrix comprisescomminuted naturally occurring extracellular matrix.
 11. The device ofclaim 10, wherein the comminuted naturally occurring extracellularmatrix is lyophilized.
 12. The device of claim 9, wherein the naturallyoccurring extracellular matrix comprises tissue selected from the groupconsisting of: vertebrate small intestine submucosa; vertebrate liverbasement membrane; vertebrate bladder submucosa; vertebrate stomachsubmucosa; vertebrate alimentary tissue; vertebrate respiratory tissue;and vertebrate genital tissue.
 13. The device of claim 12, wherein thenaturally occurring extracellular matrix comprises tissue selected fromthe group consisting of: bovine tissue; ovine tissue; and porcinetissue.
 14. The device of claim 9, wherein the anchor is formed ofnaturally occurring extracellular matrix cured and shaped to fasten intoa subchondral portion of the bone.
 15. The device of claim 14, whereinthe anchor comprises (i) a head portion configured to support the plug,and (ii) a body portion extending from the head portion to fasten intothe subchondral portion of the bone.
 16. The device of claim 9, furthercomprising a cover disposed over at least part of an articular surfaceof the plug, wherein the cover comprises one or more sheets of naturallyoccurring extracellular matrix.
 17. A device for repairing a diseased ordamaged portion of articular cartilage on a bone of a joint, thecartilage having been prepared by forming an opening therein to removethe diseased or damaged portion, the device comprising: a plugconfigured to be positioned in the opening formed in the cartilage,wherein (i) the plug comprises naturally occurring extracellular matrix,and (ii) the plug has an outer articular surface and one or more sidesurfaces extending therefrom, an anchor configured to position and holdthe plug in the opening, and a cover disposed over at least part of thearticular surface of the plug, wherein the cover comprises one or moresheets of naturally occurring extracellular matrix.
 18. The device ofclaim 17, wherein the naturally occurring extracellular matrix comprisescomminuted naturally occurring extracellular matrix.
 19. The device ofclaim 17, wherein the comminuted naturally occurring extracellularmatrix is lyophilized.
 20. The device of claim 17, wherein the naturallyoccurring extracellular matrix comprises tissue selected from the groupconsisting of: vertebrate small intestine submucosa; vertebrate liverbasement membrane; vertebrate bladder submucosa; vertebrate stomachsubmucosa; vertebrate alimentary tissue; vertebrate respiratory tissue;and vertebrate genital tissue.
 21. The device of claim 20, wherein thenaturally occurring extracellular matrix comprises tissue selected fromthe group consisting of: bovine tissue; ovine tissue; and porcinetissue.
 22. The device of claim 17, wherein the anchor is formed ofnaturally occurring extracellular matrix cured and shaped to fasten intoa subchondral portion of the bone.
 23. The device of claim 22, whereinthe anchor comprises (i) a head portion configured to support the plug,and (ii) a body portion extending from the head portion to fasten intothe subchondral portion of the bone.